Narrow write head pole tip fabricated by sidewall processing

ABSTRACT

The magnetic head includes a P 2  pole tip in which the P 2  pole tip material is electroplated upon a sidewall of the P 2  pole tip photolithographic trench. To accomplish this, a block of material is deposited upon a write gap layer, such that a generally straight, vertical sidewall of the block of material is disposed at the P 2  pole tip location. Thereafter, an electroplating seed layer is deposited upon the sidewall. A P 2  pole tip trench is photolithographically fabricated such that the sidewall (with its deposited seed layer) is exposed within the P 2  pole tip trench. Thereafter, the P 2  pole tip is formed by electroplating pole tip material upon the seed layer and outward from the sidewall within the trench. The width of the P 2  pole tip is thus determined by the quantity of pole tip material that is deposited upon the sidewall.

CROSS-REFERENCE TO RELATED APPLICATION

This is a divisional application of U.S. patent application Ser. No.09/944,648 filed Aug. 31, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the fabrication of magneticheads, and more particularly to the fabrication of a narrow second polesection (P2) for such magnetic heads.

2. Description of the Prior Art

Hard disk drives include one or more magnetic disks upon which data iswritten by magnetic heads. The ongoing efforts to increase the amount ofdata stored on the disk necessarily focuses on increasing the areal datastorage density of the disk; that is, the number of data bits that arestored within a given area of disk surface.

As is well understood by those skilled in the art, one way to increasethe areal data storage density of a hard disk 12 is to increase thenumber of tracks per inch (TPI) that are written onto the disk surface.To increase the TPI it is necessary to write narrower data tracks, andsuch narrower data tracks are achieved by decreasing the width of the P2pole tip, in that the width of the P2 pole tip generally determines thewidth of the data track that is written by a magnetic head. The standardP2 pole tip fabrication process involves the use of photolithographictechniques to create a narrow P2 pole tip trench, followed by theplating up of the P2 pole tip from the bottom of the trench to its top.In this photolithographic fabrication process, the width of the P2 poletip corresponds to the width of the P2 pole tip trench. As is understoodby those skilled in the art, limitations exist in thesephotolithographic techniques for fabricating P2 pole tips, particularlywhere high aspect ratio P2 pole tip plating trenches are required, suchthat the width of such P2 pole tips will generally reach a minimum limitof approximately 500 nm. Thus, where it is desired to create P2 poletips having a pole tip width that is less than approximately 500 nm adifferent photolithographic fabrication method is desirable, and thepresent invention is such a method for fabricating narrow P2 pole tipsin which the electroplating of the P2 pole tip is conducted principallyfrom the sidewall of the P2 pole tip trench rather than its bottom.

SUMMARY OF THE INVENTION

The magnetic head of the hard disk drive of the present inventionincludes a P2 pole tip that is fabricated utilizing photolithographicand electroplating techniques in which the P2 pole tip material iselectroplated upon a sidewall of the P2 pole tip photolithographictrench. To accomplish this, a block of material is deposited upon awrite gap layer, such that a generally straight, vertical sidewall ofthe block of material is disposed at the P2 pole tip location.Thereafter, an electroplating seed layer is deposited upon the sidewall.Utilizing photolithographic techniques, a P2 pole tip trench isfabricated such that the sidewall (with its deposited seed layer) isexposed within the P2 pole tip trench. Thereafter, the P2 pole tip isformed by electroplating pole tip material upon the seed layer. It istherefore significant that the P2 pole tip is fabricated byelectroplating material outward from the sidewall within the trench,rather than from the bottom of the trench as is known in the prior art.As a result, the width of the P2 pole tip is determined by the quantityof pole tip material that is deposited upon the sidewall, rather than bythe width of the P2 pole tip trench.

Following the fabrication of the P2 pole tip of the present invention,an induction coil is fabricated utilizing standard photolithographictechniques and a third pole section (P3) is fabricated over theinduction coil in magnetic interconnection with the P2 pole tip. The P2pole tip of the present invention therefore includes a side portion thatis composed of the seed layer that was deposited upon the sidewall ofthe block of material, and a second portion that is composed of the poletip material that was electroplated onto the seed layer. The width ofthe P2 pole tip is therefore determined by electroplating parameters,rather than by the width of the photolithographic P2 pole tip trench inwhich the P2 pole tip is fabricated.

It is an advantage of the magnetic head of the present invention that itincludes a P2 pole tip having a narrow width.

It is another advantage of the magnetic head of the present inventionthat it includes a narrow P2 pole tip for writing narrow data tracks toa magnetic hard disk.

It is an advantage of the hard disk drive of the present invention thatit includes magnetic hard disks having an increase areal data storagedensity.

It is another advantage of the hard disk drive of the present inventionthat it includes a magnetic head of the present invention that includesa P2 pole tip having a narrow width.

It is a further advantage of the hard disk drive of the presentinvention that it includes a magnetic head of the present invention thatincludes a narrow P2 pole tip for writing narrow data tracks to amagnetic hard disk.

It is an advantage of the method for fabricating a magnetic head of thepresent invention that a high aspect ratio P2 pole tip is more easilyfabricated.

It is another advantage of the method for fabricating a magnetic head ofthe present invention that it includes a narrow P2 pole tip that isfabricated utilizing photolithographic and electroplating techniques inwhich the P2 pole tip is plated from a side of the P2 pole tip trench.

These and other features and advantages of the present invention will nodoubt become apparent to those skilled in the art having read thefollowing detailed description which makes reference to the severalfigures of the drawings.

IN THE DRAWINGS

FIG. 1 is a top plan view depicting a hard disk drive of the presentinvention including a magnetic head of the present inventiontherewithin;

FIG. 2 is a top plan view of a portion of a wafer substrate depicting afirst step in the fabrication of the magnetic head of the presentinvention;

FIG. 3 is a side cross-sectional view of the device depicted in FIG. 2,taken along lines 3—3 of FIG. 2;

FIG. 4 is a top plan view of a further step in fabricating the magnetichead of the present invention;

FIG. 5 is a side cross-sectional view of the fabrication step depictedin FIG. 4, generally taken along lines 5—5 of FIG. 4;

FIG. 6 is a top plan view depicting a further fabrication step of themagnetic head of the present invention;

FIG. 7 is a side elevational view of the fabrication step depicted inFIG. 6 taken along lines 7—7 of FIG. 6;

FIG. 8 is a top plan view of a further fabrication step of the magnetichead of the present invention;

FIG. 9 is a side cross-sectional view of the fabrication step depictedin FIG. 8 taken along lines 9—9 of FIG. 8;

FIG. 10 is a top plan view of a further fabrication step of the magnetichead of the present invention;

FIG. 11 is a side cross-sectional view of the fabrication step depictedin FIG. 10 taken along lines 11—11 of FIG. 10;

FIG. 12 is a top plan view of another fabrication step of the magnetichead of the present invention;

FIG. 13 is a side cross-sectional view of the fabrication step depictedin FIG. 12, taken along lines 13—13 of FIG. 12;

FIG. 14 is a side cross-sectional view depicting a further fabricationstep of the magnetic head of the present invention taken along lines13—13 of FIG. 12;

FIG. 15 is a side cross-sectional view depicting still a furtherfabrication step of the magnetic head of the present invention takenalong lines 13—13 of FIG. 12; and

FIG. 16 is a side cross-sectional view depicting yet another fabricationstep of the magnetic head of the present invention taken along lines13—13 of FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a top plan view that depicts significant components of a harddisk drive which includes the magnetic head of the present invention.The hard disk drive 10 includes a magnetic media hard disk 12 that isrotatably mounted upon a motorized spindle 14. An actuator arm 16 ispivotally mounted within the hard disk drive 10 with a magnetic head 20of the present invention disposed upon a distal end 22 of the actuatorarm 16. A typical hard disk drive 10 may include a plurality of disksthat are rotatably mounted upon the spindle 14 and a plurality ofactuator arms 16 having a magnetic head 20 mounted upon the distal end22 of the actuator arms. As is well known to those skilled in the art,when the hard disk drive 10 is operated, the hard disk 12 rotates uponthe spindle 14 and the magnetic head 20 acts as an air bearing sliderthat is adapted for flying above the surface of the rotating disk. Theslider includes a substrate base upon which the various structures thatform the magnetic head are fabricated. Such heads are fabricated inlarge quantities upon a wafer substrate and subsequently sliced intodiscrete magnetic heads 20.

As is well known to those skilled in the art typical magnetic headfabrication steps generally include the deposition and patterning ofvarious thin film layers to fabricate a read head, followed by thefurther deposition and patterning of various thin film layers upon theread head to fabricate a write head. The present invention relates tothe fabrication of a write head, and therefore a magnetic head of thepresent invention may include most, if not all, of the various read headconfigurations as are generally known to those skilled in the art. Thus,a detailed description of the fabrication process of the presentinvention can commence at a point in the magnetic head fabricationprocess that a read head element has been fabricated upon a wafersubstrate, followed by the fabrication of a P1 magnetic pole and a writegap layer. Such structures are well known to those skilled in the art,and a detailed description thereof is not required to present a detaileddescription of the present invention.

FIGS. 2 and 3 depict first steps in the fabrication of a P2 pole tip ofthe magnetic head 20 of the present invention, wherein FIG. 2 is a topplan view and FIG. 3 is a side cross-sectional view taken along lines3—3 of FIG. 2. As depicted in FIGS. 2 and 3, the fabrication process ofa magnetic head upon a wafer substrate surface has been conducted to thepoint of the fabrication of a first pole (P1) 30 upon an insulationlayer (not shown) followed by the deposition of a write gap layer 34upon the P1 pole 30. As indicated above, the fabrication of magneticheads to this point is well known to those skilled in the art. Followingthe deposition of the write gap layer 34, a block of nonconductivematerial 40 is fabricated upon the write gap layer. The block ofmaterial 40 can be fabricated in a variety of ways, such as bydepositing a photoresist and photolithographically patterning andremoving portions of the photoresist such that the block of materialremains. The significant features of the block of material are that itsheight h should correspond to the height of the desired P2 pole tip,that its thickness t corresponds to the desired thickness of the P2 poletip, that the block 40 be positioned such that its sidewall 44 beaccurately located above the P1 pole at the desired location of the P2pole tip, and that the sidewall 44 be smooth and vertical. Thereafter,as is depicted in FIGS. 2 and 3, a seed layer 50 for the electroplatingof the P2 pole tip is deposited across the surface of the wafer,significantly including a seed layer portion 54 that is deposited tocover the sidewall 44. The seed layer 50 is preferably composed of thesame material as the pole tip, such as NiFe, and is deposited using atypical sputter deposition technique.

A further step in the fabrication of the magnetic head of the presentinvention is depicted in FIGS. 4 and 5, wherein FIG. 4 is a top planview and FIG. 5 is a side cross-sectional view taken along lines 5—5 ofFIG. 4. As depicted in FIGS. 4 and 5, following the deposition of theseed layer, a photoresist layer 60 is deposited on top of the seed layer50 and across the surface of the wafer. Thereafter, utilizingphotolithographic techniques, a P2 pole tip trench 64 isphotolithographically formed in the photoresist layer 60. Significantly,the P2 pole tip trench is located to expose the seed layer 54 depositedupon the sidewall 44. The width r of the P2 pole tip trench 64 is chosento be sufficiently wide to allow unimpeded electroplating of the P2 poletip within the trench 64 as is next described with the aid of FIGS. 6and 7, wherein FIG. 6 is a top plan view of the electroplating step andFIG. 7 is a side cross-sectional view taken along lines 7—7 of FIG. 6.

As depicted in FIGS. 6 and 7, the P2 pole tip material 70 is nextelectroplated onto the exposed seed layer 50 utilizing standardelectroplating techniques as are known to those skilled in the art. Itis significant that the P2 pole tip material 70 is electroplated outwardfrom the seed layer portion 54 deposited upon the sidewall 44. That is,the critical width dimension of the P2 pole tip is now determined by theelectroplating parameters related to the thickness of the electroplatedlayer as is further described hereinbelow. Thus the width of the P2 poletip is not determined by the width of the P2 pole tip trench, as is donein the prior art. As a result, the prior art problems associated withlimits upon the aspect ratio of the P2 pole tip trench in thephotolithographic process are no longer significant.

Following the electroplating step, the photoresist 60 is removed,preferably using a wet chemical process, and FIG. 8 is a top plan viewdepicting the device following photoresist removal and FIG. 9 is a sidecross-sectional view taken along lines 9—9 of FIG. 8 that likewisedepicts the device following the removal of the photoresist. In afollowing step, as depicted in FIGS. 8 and 9 the seed layer 50 isremoved preferably utilizing an ion beam milling step, typicallyutilizing argon, as is known to those skilled in the art. FIG. 10 is atop plan view of the device following the removal of the seed layer andFIG. 11 is a side cross-sectional view taken along lines 11—11 of FIG.10, depicting the device following the removal of the seed layer in theion milling step. With reference to FIGS. 8, 9, 10 and 11, and as can beparticularly seen by comparing FIGS. 9 and 11, the ion milling step isconducted for a sufficient time period to remove the upper, overlaidportion 74 of the electroplated pole tip material and the lower overlaidportion 78 of the P2 pole tip material, such that the remaining portionof the P2 pole tip 80 includes portions of the seed layer 54 depositedupon the sidewall 44 and the P2 pole tip material 88 that has beenelectroplated onto the seed layer 54. Thereafter, as depicted in FIGS.10 and 11, the resist block 40 is removed in a further wet chemicalprocess, such that only the P2 pole tip structure 80 remains on thewrite gap surface 34. It can now be clearly seen that the width W of theP2 pole tip 80 is comprised of the thickness of the seed layer 54deposited upon the sidewall 44 plus the thickness of the pole tipmaterial 88 electroplated onto the sidewall seed layer 54. Furthermore,as indicated above, the width W of the P2 pole tip has been determinedin the electroplating process by selection of appropriate electroplatingprocess parameters rather than by the width of the P2 pole tip platingtrench 64.

With the P2 pole tip 80 fabricated on the wafer surface, as depicted inFIGS. 10 and 11, a P1 notching process can now be advantageouslyconducted. As will be understood by those skilled in the art, apatterned ion etching mask is fabricated upon the wafer substrate suchthat the P2 pole tip 80 and portions of the write gap layer adjacentthereto are exposed to an ion milling beam. As depicted in FIGS. 10 and11, the ion milling is conducted to remove portions of the write gaplayer 34 adjacent to the P2 pole tip 80 and to mill a notch 92 into theP1 pole 30. As is known to those skilled in the art, P1 pole notchingadvantageously reduces side writing effects of a magnetic head. Where P1pole notching is not desired, the block of material 40 can be allowed toremain on the write gap layer 34 to support the P2 pole tip 80, and thefabrication of the induction coil (as is next described) can becommenced.

As is next depicted in FIGS. 12 through 16, further fabrication steps,as are known to those skilled in the art, are next conducted to completethe fabrication of the magnetic head. Thus, as depicted in FIGS. 12 and13, wherein FIG. 12 is a top plan view of the head, and FIG. 13 is aside cross-sectional view taken along lines 13—13 of FIG. 12, aninduction coil is fabricated upon the wafer surface by photolithographictechniques to create an induction coil trench 100 within an insulationlayer 104, followed by electroplating techniques to electroplate theinduction coil 108, typically composed of copper, into the inductioncoil trench 100. Therefore, as depicted in FIG. 12, the induction coiltrench is located immediately above the previously fabricated P2 poletip 80. Alternatively, as is known to those skilled in the art, theinduction coil can be fabricated utilizing a suitable dielectricmaterial layer and a reactive ion etching process to create theinduction coil trench, followed by the electroplating of the inductioncoil therewithin. As is next depicted in FIG. 14, a chemical mechanicalpolishing (CMP) step is conducted to remove any excess induction coilmaterial and to achieve a planar surface 112 upon the wafer. Thereafter,a patterned insulation layer 116 is deposited on top of the inductioncoil. Significantly, the insulation layer 116 is not deposited upon thetop surface of the P2 pole tip 80. As is next depicted in FIG. 15, afurther magnetic pole piece 120 (sometimes referred to as a P2 pole yokeor a P3 pole) is fabricated upon the surface of the insulation layer andin magnetic connection with the P2 pole tip 80. The P3 pole 120 ispreferably fabricated utilizing photolithographic techniques andelectroplating techniques as are well known to those skilled in the art.As depicted in FIG. 15, the P3 pole is preferably fabricated upon the P2pole tip, such that a gap 124 is provided between the end surface 128 ofthe P3 pole and the end surface 132 of the P2 pole tip 80. When thewafer level fabrication steps are completed, the wafer is sliced tocreate rows of magnetic heads. As depicted in FIG. 16, the air bearingsurface (ABS) 148 is then fabricated, such that the gap 124 remains.Thereafter, further magnetic head fabrication steps are conducted, asare well known to those skilled in the art, and encapsulation layer 140is ultimately fabricated upon the device. Further fabrication steps asare well known to those skilled in the art are then undertaken tocomplete the fabrication of the magnetic head 20 of the presentinvention.

It is therefore to be understood that a significant feature of thepresent invention is that the width W of the P2 pole tip 80 isdetermined in the electroplating process steps by the deposition of P2pole tip material 88 upon the sidewall seed layer 54. Thus, through thepresent invention, a P2 pole tip 80 is fabricated wherein the width W isdetermined by the thickness of the sidewall seed layer 54 plus thethickness of the electroplated material 88 layer thereon. For example, aP2 pole tip 80 of the present invention may be fabricated wherein thesidewall seed layer thickness is approximately 50 Å to 500 Å and theelectroplated material thickness is approximately 100 Å to 5000 Å, suchthat the P2 pole tip width W is approximately 150 Å to 5500 Å. In thepreferred embodiment the seed layer thickness is approximately 250 Å andthe electroplated material thickness is approximately 1500 Å, such thatthe width W of the P2 pole tip is approximately 1750 Å. The thicknessdimension t of the P2 pole tip 80 is controlled by the thickness t ofthe deposited sidewall, less material removed from the top of the P2pole tip during P1 pole notching, if conducted. Thus, as will beunderstood by those skilled in the art, the width W of the P2 pole tip80 of the present invention is now within the control of the magnetichead electroplating step, and not controlled by the photolithographicaspect ratio problems encountered in the prior art. Thus the prior artP2 pole tip fabrication problems associated with the aspect ratio of thephotolithographically created P2 pole tip trench are overcome.

While the present invention has been shown and described with regard tocertain preferred embodiments, it will be understood that those skilledin the art will no doubt develop certain alterations and modificationsand form and detail. It is therefore intended that the following claimscover all such alterations and modifications that nevertheless includethe true spirit and scope of the present invention.

1. A method for fabricating a magnetic head, comprising the steps of:fabricating a read head upon a substrate; fabricating a P1 pole uponsaid read head; fabricating a write gap layer upon said P1 pole;fabricating a block of material upon said write gap layer, said block ofmaterial having a sidewall disposed proximate a P2 pole tip location;fabricating a seed layer upon said sidewall; electroplating P2 pole tipmaterial upon said seed layer, whereby a P2 pole tip is formed having awidth W that is comprised of a thickness of said seed layer material anda thickness of said electroplated material; fabricating an inductioncoil proximate said P2 pole tip; fabricating a P3 pole above saidinduction coil in magnetic interconnection with said P2 pole tip; andfabricating an encapsulation layer above said P3 pole.
 2. A method forfabricating a magnetic head as described in claim 1 wherein said seedlayer is fabricated to a thickness of approximately 50 Å toapproximately 500 Å.
 3. A method for fabricating a magnetic head asdescribed in claim 1 wherein said electroplated material is fabricatedto a thickness of approximately 100 Å to approximately 5000 Å.
 4. Amethod for fabricating a magnetic head as described in claim 1 whereinsaid seed layer is fabricated to a thickness of approximately 50 Å toapproximately 500 Å, and wherein said electroplated material isfabricated to a thickness of approximately 100 Å to approximately 5000Å.
 5. A method for fabricating a magnetic head as described in claim 4wherein said seed layer is fabricated to a thickness of approximately250 Å and said electroplated material is fabricated to a thickness ofapproximately 1500 Å.
 6. A method for fabricating a magnetic head asdescribed in claim 4, wherein said seed layer is comprised of NiFe andsaid P2 pole tip material that is electroplated upon said seed layer iscomprised of NiFe.
 7. A method for fabricating a magnetic head asdescribed in claim 1 wherein said P2 pole tip is fabricated within a P2pole tip trench having width that is wider than said width W of said P2pole tip.
 8. A method for fabricating a magnetic head as described inclaim 1 wherein said block of material is removed from said write gaplayer following said electroplating of said P2 pole tip material, andsaid P1 pole is notched in an ion milling step.
 9. A method forfabricating a magnetic head as described in claim 1, wherein saidsidewall comprises a planar surface that is disposed perpendicularly tosaid write gap layer.